A Black Hole in the Superluminal Source SAX J1819.3−2525 (V4641 Sgr)

Orosz, Jerome A.; Kuulkers, E.; Klis, M. van der; McClintock, Jeffrey E.; Garcia, M. R.; Callanan, P. J.; Bailyn, Charles D.; Jain, R. K.; Remillard, Ronald A.

doi:10.1086/321442

Cited by 231 publications

(307 citation statements)

References 33 publications

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“…In the interim, the abundance excesses for X-ray absorption edges in GRS 1915]105 can be contrasted with the discovery of abundance anomalies in the optical spectra of companion stars in the microquasars GRO J1655[40 and V4641 Sgr (Israelian et al 1999 ;Brown et al 2000 ;Orosz et al 2001). In the latter cases, the overabundances of aprocess elements, but not the Fe group, have led to the hypothesis that the companion star captured supernova or hypernova ejecta is related to the formation of the black hole.…”

Section: Discussionmentioning

confidence: 99%

High‐ResolutionChandraHETGS andRossi X‐Ray Timing ExplorerObservations of GRS 1915+105: A Hot Disk Atmosphere and Cold Gas Enriched in Iron and Silicon

Lee

Reynolds

Remillard

et al. 2002

ApJ

220

284

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The time-averaged 30 ks Chandra AO1 High Energy Transmission Grating Spectrometer observation of the microquasar GRS 1915]105 in the low hard state reveals for the Ðrst time in this source neutral K absorption edges from iron, silicon, magnesium, and sulphur. Ionized resonance (r) absorption from H-and He-like species of Fe (XXV, XXVI) and possibly Ca XX are also seen as well as possible emission from neutral Fe Ka and ionized Fe XXV (forbidden or the resonance emission component of a P Cygni proÐle). We report the tentative detection of the Ðrst astrophysical signature of X-ray absorption Ðne structure in the photoelectric edge of Si (and possibly Fe and Mg) attributed to material in grains. The large column densities measured from the neutral edges reveal anomalous Si and Fe abundances and illustrate the importance of high-resolution X-ray measurements for assessing material that surrounds bright X-ray sources, especially if depletion onto grains plays a prominent role. Scenarios for which the anomalous abundances can be attributed to surrounding cold material associated with GRS 1915]105 and/or for which the enrichment may signify either a highly unusual supernova/hypernova or external supernova activity local to the binary are discussed. We attribute the ionized features to a hot disk, disk wind, or corona environment. Based on H-and He-like Fe (XXV, XXVI), we estimate constraints on the ionization parameter temperature (T [ 2.4 ] 106 K), and hydrogen equivalent number (log m Z 4.15), density cm~3) for this region. Variability studies with the simultaneous RXT E data show that (n Z 1012 the light-curve count rate tracks the changes in the disk blackbody as well as the power-law Ñux, with the most signiÐcant variations observed in the former. The Chandra data show spectral changes that also track the behavior of the light curve and may point to changes in both the ionizing Ñux and density of the absorber. A 3.69 Hz quasi-periodic oscillation and weak Ðrst harmonic are seen in the RXT E data.

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Section: Discussionmentioning

confidence: 99%

High‐ResolutionChandraHETGS andRossi X‐Ray Timing ExplorerObservations of GRS 1915+105: A Hot Disk Atmosphere and Cold Gas Enriched in Iron and Silicon

Lee

Reynolds

Remillard

et al. 2002

ApJ

220

284

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“…Therefore, it would be interesting to analyze other elements such as O, Mg, and C, which are enhanced in many of the model computations in Tables 4 and 5, even at high mass cuts. We note that Orosz et al (2001) have also found overabundances (by a factor 2-10 with respect to solar) of some of these elements in the secondary star of the LMXB system J1819.3À2525 (V4641 Sgr).…”

Section: Evv Olutionary Scenariomentioning

confidence: 63%

Chemical Abundances in the Secondary Star in the Black Hole Binary A0620−00

Hernández

Rebolo

Israelian

et al. 2004

ApJ

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Using a high-resolution spectrum of the secondary star in the black hole binary A0620À00, we have derived the stellar parameters and veiling caused by the accretion disk in a consistent way. We have used a 2 minimization procedure to explore a grid of 800,000 LTE synthetic spectra computed for a plausible range of both stellar and veiling parameters. Adopting the best model parameters found, we have determined atmospheric abundances of Fe, Ca, Ti, Ni, and Al. The Fe abundance of the star is ½Fe=H ¼ 0:14 AE 0:20. Except for Ca, we found the other elements moderately overabundant as compared with stars in the solar neighborhood of similar iron content. Taking into account the small orbital separation, the mass transfer rate, and the mass of the convection zone of the secondary star, a comparison with element yields in supernova explosion models suggests a possible explosive event with a mass cut comparable to the current mass of the compact object. We have also analyzed the Li abundance, which is unusually high for a star of this spectral type and relatively low mass.

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“…We also speculate that Fe may be overabundant (relative to solar) by a factor of a few in this source. Orosz et al (2001) report that N and Ti may be overabundant by a factor of 10, Mg by a factor of 7, O by a factor of 3, and Ca by a factor of 2.…”

Section: Discussionmentioning

confidence: 99%

“…In particular, advectiondominated accretion flow (ADAF) models for transient systems (e.g., Esin, McClintock, & Narayan 1997) Orosz et al 2001). Hjellming et al (2000) mond ≤ 12.31 itored the outburst in radio and found jets expanding at apparently superluminal velocities; V4641 Sgr is therefore termed a "microquasar."…”

mentioning

confidence: 99%

A Relativistic F[CLC]e[/CLC] Kα Emission Line in the Intermediate-Luminosity [ITAL]B[CLC]eppo[/CLC]SAX[/ITAL] Spectrum of the Galactic Microquasar V4641 Sgr

Miller

Fabian

Zand

et al. 2002

The Astrophysical Journal

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A Black Hole in the Superluminal Source SAX J1819.3−2525 (V4641 Sgr)

Abstract: Spectroscopic observations of the fast X-ray transient and superluminal jet source SAX J1819.3[2525 (V4641 Sgr) reveal a best-Ðtting period of days and a semiamplitude of P spect \ 2

Cited by 231 publications

References 33 publications

High‐ResolutionChandraHETGS andRossi X‐Ray Timing ExplorerObservations of GRS 1915+105: A Hot Disk Atmosphere and Cold Gas Enriched in Iron and Silicon

High‐ResolutionChandraHETGS andRossi X‐Ray Timing ExplorerObservations of GRS 1915+105: A Hot Disk Atmosphere and Cold Gas Enriched in Iron and Silicon

Chemical Abundances in the Secondary Star in the Black Hole Binary A0620−00

A Relativistic F[CLC]e[/CLC] Kα Emission Line in the Intermediate-Luminosity [ITAL]B[CLC]eppo[/CLC]SAX[/ITAL] Spectrum of the Galactic Microquasar V4641 Sgr

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